import sched,time,string,json
from threading import Thread
from sys import exit
class TaskPool:
	def __init__(self,**kwargs):
		self.base_state = kwargs
		self.base_state["task_pool"] = self
		self.scheduler = sched.scheduler(time.time,time.sleep)
		self.thread = Thread(target=self.worker,args=(self,))
		self.coroutines = []
		self.states = {}
		self.killswitch = False

	def periodical(self,scheduler,interval,action,index,state=dict()):
		if self.killswitch:
			return

		self.states[index] = action(state,self.base_state)
		if not self.killswitch:
			scheduler.enter(interval,1,self.periodical,(scheduler,interval,action,index,self.states[index]))

	def worker(self,tasks):
		for c,coro in enumerate(tasks.coroutines):
			interval = coro["interval"]
			action = coro["action"]
			state = coro.get("state",dict())
			tasks.periodical(tasks.scheduler,interval,action,c,state)
		tasks.scheduler.run()
		exit(0)

	def run(self):
		if self.thread.is_alive(): return # don't set up an already set-up thread
		self.thread.daemon = True
		self.thread.start()

	def stop(self):
		list(map(self.scheduler.cancel, self.scheduler.queue))
		self.killswitch = True # kill any lingering tasks

	def add_coroutine(self,action,interval,state=dict(),name=None):
		if name is None:
			name = string.ascii_letters[len(self.coroutines)]
		self.coroutines.append(dict(action=action,interval=interval,state=state,name=name))

	def save_state(self, index):
		with open("state.{}.json".format(self.coroutines[index]["name"]),"w") as f:
			json.dump(self.states[index],f)

	def load_state(self, index):
		try:
			with open("state.{}.json".format(self.coroutines[index]["name"])) as f:
				self.states[index] = json.load(f)
				self.coroutines[index]["state"] = self.states[index]
		except:
			print("state.{}.json not found or couldn't be opened; using default".format(self.coroutines[index]["name"]))